The present invention relates to an addition-reacting silicone pressure-sensitive adhesive composition which cures to give a pressure-sensitive adhesive.
Silicone pressure-sensitive adhesives have an excellent adhesive strength, tack, and cohesive strength, which are the properties required of a pressure-sensitive adhesive. In addition, they also have the heat resistance, cold resistance, and electrical properties, etc., characteristic of silicones, and so are widely used for electric-insulating tape, which must be very reliable, and for various pressure-sensitive products which must be resistant to hot and cold.
In general, organoperoxide-curing compositions (consisting of a mixture of dimethylsiloxane polymer and methylsiloxane resin) are used as silicone pressure sensitive adhesive compositions. A composition which cures by the addition reaction between alkenyl-containing organopolysiloxane and organopolysiloxane having silicon-bonded hydrogen atoms has also been proposed. Refer to Japanese Patent Publication Number 54-37907 (37,907/79).
However, such organoperoxide-curing compositions must be cured by heating at high temperatures, at least 130 degrees Centigrade, in order to convert them into the pressure-sensitive adhesive. As a consequence, they cannot be used with poorly heat-tolerant substrates. At the same time, while the aforementioned addition-curing composition can in fact be cured at lower temperatures than the organoperoxide-curing compositions, the adhesive strength of the former is inferior to that of the latter.
The inventors carried out investigations in order to eliminate these problems residing in the prior art, and the present invention was developed as a consequence.